Stoneware
a very hard kind of pottery, with which are made jars, drain pipes, and a variety of chemical utensils.
It is constituted of plastic clay, united in various proportions with some felspathic mineral sands of different kinds, and in some cases with cement, stone, or chalk.
These mixtures are then subjected to a heat sufficiently great to cause a partial fusion of the mass. This condition of semi-fusion is the distinguishing character of stoneware. The finer varieties of stoneware are made from carefully selected clays, which when burnt will not have much color. These are united with some fluxing substance, by which the particular state of semi-fusion above mentioned, is brought about. Formerly the glaze of stoneware was always a salt glaze; recently, however, it has been customary to glaze with a mixture of Cornish stone, flint, etc., as in the manufacture of earthenware. See POTTERY.